Foundation structure for mobile home

ABSTRACT

A foundation structure for mobile homes, comprising a prestressed, or post-stressed, lightweight concrete base, having longitudinally and transversely extending flanges on the underside, which give it structural stiffness and rigidity. The concrete base is much heavier than the conventional steel framework underbody, and a larger proportion of the total mass is incorporated in the foundation structure, so that the center of gravity of the complete mobile home is lowered to a level just about at the tops of the wheels, making it very stable. Cast concrete underbody requires less labor to build, its cost is less, no painting is required, needs no wood floor and therefor is less susceptible to termites, and conduits for plumbing, electric wires, and ventilation air can be cast in place. Prestressed steel reinforcing rods or cables are embedded in the flanges, and are bent to obtain maximum vertical force vectors at the ends of the concrete structure.

United States Patent [191 Jones [111 3,811,722 [451 Mayzl, 1974 FOUNDATION STRUCTURE FOR MOBILE HOME [76] Inventor: George T. Jones, PO. Box 32l7,

Blue Jay, Calif. 92317 [22] Filed: Dec. 7, 1972 [21] Appl. No.: 311,739

[52] US. Cl. 296/23 R, 296/31 R, 52/73 [51] Int. Cl B60b 3/32 [58] Field of Search 296/23 R, 31 R; 52/73, 7 52/79, 223

[56] References Cited UNITED STATES PATENTS 3,716,267 7/1973 Lindsay "296/23 R 925,964 6/1909 Strauss 296/31 R 1,574,180 2/l926 Strauss 296/31 R Primary Examiner-PhilipGoodman Attorney, Agent, or Firm-Herbert E. Kidder [57] ABSTRACT A foundation structure for mobile homes, comprising a prestressed, or post-stressed, lightweight concrete base, having longitudinally and transversely extending flanges on the underside, which give it structural stiffness and rigidity. The concrete base is much heavier than the conventional steel framework underbody, and a larger proportion of the total mass is incorporated inthe foundation structure, so that the center of gravity of the complete mobile home is lowered to a level just about at the tops of the wheels, making it very stable. Cast concrete underbody requires less labor to build, its cost is less, no painting is required,

needs no wood floor and therefor is less susceptible to termites, and conduits for plumbing, electric wires, and ventilation air can be cast in place. Prestressed steel reinforcing rods or cables are embedded in the flanges, and are bent to obtain maximum vertical force vectors at the ends of the concrete structure.

5 Claims, 6 Drawing Figures m gmiulmm 1974 FIG. 3

FIG. 6

FOUNDATION STRUCTURE-FOR MOBILE HOME BACKGROUND OF THE INVENTION The present invention pertains to a base frame structure, or foundation, upon which a mobile home is supported.

The conventional practice in building mobile homes is to fabricate the base frame of steel beams which are welded, riveted, or bolted together. A wood floor is secured to the top side of this frame, and the walls of the mobile home are then built up from the wood floor, more or less in the same manner that conventional homes are constructed. A steel base frame constructed as just described has the following disadvantages: (1) it has an undesirable amount of flexibility, owing to the elasticity of the steel beams, and this requires that the walls be utilized asstructural members to give the structure rigidity; (2) the relatively light weight of the steel base frame results in a high center of gravity, which reduces the stabilityof the structure when being towed in strong, gusty cross winds; (3) a wood floor is needed to bridge the open spaces between steel frame members, and this is vulnerable to tennites; and (4) a fabricated steel base frame is relatively expensive to build and requires much skilled labor to put it together.

. SUMMARY OF, THE INVENTION:

The primary object of the present invention is to providea base frame structure for mobilehomes, that is inherently stiff and relatively inflexible, and which is completely self-supporting and does not require the structural reinforcement of the walls orother parts of the dwelling structure. With the walls thus relieved of all structural stresses in the base frame, it is possible to build into the walls large areas of window glass or other details which do not lend themselves to-carrying structural stresses.

Another importantobject of the invention is to provide a foundation, or base frame structure, for a mobile home, which is considerably heavier than the conventional steel base frame, causing the center of gravity of the entire structure to be lowered to a level just about at the tops of the wheels. This adds greatly to the stability of the mobile home, and makes it safer to tow in strong, gusty cross winds. V g Another object of the invention is to provide a base frame for a mobile home, which requires no wood floors, and therefore is less susceptible to damage from termites. Carpeting or tile canbe applied directly to the flat top surface of a base frame made in accordance with the invention. I

Still a further object of the invention is to provide a base frame structure for a mobile home that is simple and inexpensive to manufacture, requires less labor BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a mobile home constructed on a base frame structure embodying the principles of the present invention;

FIG. 2 is a bottom plan view of the same, showing the underside;

FIG. 3 is a side elevation of the base frame structure, or foundation, as it appears without the dwelling structure;

FIG. 4 is an enlarged front end view of the structure shown in FIG. 3;

FIG. 5 is a sectional view through the base frame structure, taken at 55 in FIG. 2, drawn to a somewhat larger scale; and

FIG. 6 is an enlarged fragmentary sectional view taken through the base frame structure at one side thereof.

DESCRIPTION OF, THE PREFERRED EMBODIMENT In the drawings, the mobile home'is designated in its entirety by the reference numeral 10 and comprises a dwelling unit 12 mounted on a supporting base structure, or platform 14, which is supported, in turn, by wheels 16. At the front end of the platform 14 is a forwardly extending draft tongue 18, which is connected to the usual towing connection on an automobile. The

' dwelling unit 12 may take any form, and is herein gate and entrained air. Projecting downwardly from the underside of the platform are laterally spaced, longitudinally extending flanges 24, 25, 26, 27 and 28, and a plurality of longitudinally spaced, parallel, transverse flanges 30. The two outer pairs of longitudinal flanges 24, 25 and 27, 28 are considerably deeper at the midpoint of the platform than at the ends thereof, as best seen in FIGS. 3, 4 and 5, while the center flange 26 and transverse flanges 30 are all constant in depth from one end to the other. I

' Upper and lower, lengthwise extending, steel reinforcement cables, or rods 32 and 34 are cast into the outer pairs of longitudinal flanges 24, 25, and 27, 28, and these are tensioned at the time of casting and curing the concrete, so as to give the structure maximum stiffness and rigidity. The rods 32 and 34 are also positioned and bent, as shown in broken lines in FIG. 3, so

i as to'obtain maximum vertical force vectors at the free ends of the concrete platform. This is accomplished by placing the upper rods 32 close to the top edge of the flange at the midpoint of the platform, and bending the rods downwardly on both sides of the midpoint so that their ends lie close to the bottom edges of their respective flanges at the ends of the flanges. The lower rods 34- are placed'close to the bottom edges of the flanges at the midpoint of the platform, and bent upwardly on both sides, so that their outer ends lie close to the top edges of their respective flanges at the ends thereof. Upper reinforcement bars 32 are thus positioned to resist downward deflection of the ends of the platform 14, while lower bars 34 are positioned to resist upward deflection. Other reinforcing bars 36 extend transversely across the platform, and are embedded in the transverse flanges 30 near the top and bottom edges thereof.

The wheels 16 are conventional automotive-type wheels with pneumatic tires, and are joumaled at the ends of transverse axles 38, which are connected to the bottom edges of flanges 25 and 27 by leaf springs 40. Wheels 16 are positioned between the outer pairs of flanges 24, 25 and 27, 28. While the drawing shows three tandem wheels on each side of the platform, it will be understood that any number of wheels might be used, and they can be arranged in any desired grouping.

The draft tongue 18 comprises two forwardly converging steel beams 42 and 43, and a central, fore-andaft extending beam 44, which come together and are welded to a gusset plate. A screw-jack 46 engages the ground to support the front end of the draft tongue when the latter is disconnected from its towing vehicle.

The dwelling unit 12 is built up on platform 14 in the usual way, using the top surface of the platform as a floor or sub-floor. Sills of 2X4 lumber may be cemented to the platform, using epoxy cement, or the like, or they may be attached by using fasteners that are cast into the concrete. Carpeting or tile can be applied directly to the top surface of the platform 14, or a wood flooring can be laid onto the surface. Ducts, raceways, and conduits may be cast into the platform or on the underside thereof, and vent openings48 may be provided in the floor (FIG. for heaters or air conditioner 50. FIG. 5 also shows how a horizontal panel 52 of plywood or the like material may be secured along its edges to the inner longitudinal flanges 25 and 26 a short distance below the bottom edges of the transverse flanges 30, to form a plenum chamber 54 for the heating and air-conditioning system. Thermal insulation for the floor may be formed in place on the underside of the platform 14 after the concrete has cured. This is easily done by pouring the liquid resin composition onto the inverted platform, and allowing the liquid to spread out and seek its own level as it foams.

The cement used in'making the platform 14 is preferably portland cement, although any other substance having similar properties might be used. For example, various plastic materials such as polyester resin might be substituted for portland cement, and the said resin might be used with a particulate aggregate, or glass fibers, or both. Accordingly, the term concrete as used in the claims includes any material fonned by concretion or coalescence of separate particles of matter in one body. The reinforcing rods 32, 34 may be prestressed, as described earlier, or the platform can be cast in slightly cambered form, as indicated by broken lines 54 in FIG. 3, so that it flattens out by gravity when inverted. In this latter case, the reinforcing rods are tensioned by what is called post-stressing. A I2 60 foot concrete underbody constructed in accordance with the invention weighs about 15000 pounds, whereas a steel platform and wood floor of similar size weighs approximately one-third as much. As a result of the placement of this large mass at the bottom of the mobile home, the center of gravity of the entire structure is just slightly above the level of the top of the wheels 16.

Casting the platform 14 of concrete requires relatively little labor, and the total cost of manufacturing the platform is less. No painting is required, and the concrete structure is virtually immune to corrosion or deterioriation by weathering. The concrete underbody can also be used for prefabricated modular homes, in which case there would be no wheels or axles, or draft tongue. The platform 14 would be transported to the building site on a flat bed trailer, and them becomes the foundation of the building.

While 1 have shown and described in considerable detail what I believe to be the preferred embodiment of the invention, it will be understood by those skilled in the art that the invention is not limited to such details, but might take various other forms within the scope of the claims that follow.

l claim:

1. A foundation structure for a mobile home, comprising a prefabricated rectangular platform of cast, concrete-like material, having a flat top surface which serves as a floor for the mobile home, and downwardly projecting flanges on the underside thereof, some of said flanges extending parallel to the longitudinal axis of said platform and some extending transversely with respect thereto;

a plurality of longitudinally extending tensioned reinforcing members embedded in said platform to prevent vertical flexing of the ends thereof, certain of said members being located adjacent the top surface thereof, and others of said members being located adjacent the bottom edges of said longitudinally extending flanges, said certain members being bent downwardly from the midsection of the platform to the ends thereof, and said other members being bent upwardly-from the midsection of the platform to the ends thereof; and

a plurality of wheels supporting said platform intermediate the ends thereof.

2. A foundation structure for a mobile home, comprising a prefabricated rectangular platform of cast concrete, having a flat top surface which serves as a floor for the mobile home, and downwardly projecting flanges on the underside thereof, some of said flanges extending parallel to the longitudinal axis of said platform and some extending transversely with respect thereto;

said longitudinally extending flanges being deeper at the midpoint of the platform than they are at the ends;

a plurality of longitudinally extending tensioned reinforcing members embedded in said concrete platform to prevent vertical flexing of the ends thereof, said reinforcing members comprising steel rods or cables extending lengthwise of the platfomi, some of said rods or cables being located adjacent the top surface of the platform at the midpoint thereof and bending downwardly so that their ends are adjacent the bottom edges of their respective flanges, and others of said rods or cables being located adjacent the bottom edge of their respective flanges at the midpoint of the platform and bending upwardly so that their ends are adjacent the top edges of their respective flanges;

a plurality of wheels supporting said platform intermediate the ends thereof; and

a draft tongue attached to one end of said platform and having means adapted for connection to a towing vehicle.

5. A foundation structure for a mobile home, as in claim 2, wherein said reinforcing rods or cables are post stressed by casting said platform with a slight upward'camber on either side of the midpoint, the ends of said platform then deflecting downwardly by gravity to produce a level top surface, said downward deflection of the ends serving to tension at least some of said reinforcing rods or cables. 

1. A foundation structure for a mobile home, comprising a prefabricated rectangular platform of cast, concrete-like material, having a flat top surface which serves as a floor for the mobile home, and downwardly projecting flanges on the underside thereof, some of said flAnges extending parallel to the longitudinal axis of said platform and some extending transversely with respect thereto; a plurality of longitudinally extending tensioned reinforcing members embedded in said platform to prevent vertical flexing of the ends thereof, certain of said members being located adjacent the top surface thereof, and others of said members being located adjacent the bottom edges of said longitudinally extending flanges, said certain members being bent downwardly from the midsection of the platform to the ends thereof, and said other members being bent upwardly from the midsection of the platform to the ends thereof; and a plurality of wheels supporting said platform intermediate the ends thereof.
 2. A foundation structure for a mobile home, comprising a prefabricated rectangular platform of cast concrete, having a flat top surface which serves as a floor for the mobile home, and downwardly projecting flanges on the underside thereof, some of said flanges extending parallel to the longitudinal axis of said platform and some extending transversely with respect thereto; said longitudinally extending flanges being deeper at the midpoint of the platform than they are at the ends; a plurality of longitudinally extending tensioned reinforcing members embedded in said concrete platform to prevent vertical flexing of the ends thereof, said reinforcing members comprising steel rods or cables extending lengthwise of the platform, some of said rods or cables being located adjacent the top surface of the platform at the midpoint thereof and bending downwardly so that their ends are adjacent the bottom edges of their respective flanges, and others of said rods or cables being located adjacent the bottom edge of their respective flanges at the midpoint of the platform and bending upwardly so that their ends are adjacent the top edges of their respective flanges; a plurality of wheels supporting said platform intermediate the ends thereof; and a draft tongue attached to one end of said platform and having means adapted for connection to a towing vehicle.
 3. A foundation structure for a mobile home, as in claim 2, wherein means is provided on the underside of the platform which defines a plenum chamber for the heating and ventilation system with register openings formed in the floor, through which air passes.
 4. A foundation structure for a mobile home, as in claim 2, wherein said reinforcing rods or cables are prestressed at the time the concrete is poured and cured.
 5. A foundation structure for a mobile home, as in claim 2, wherein said reinforcing rods or cables are post stressed by casting said platform with a slight upward camber on either side of the midpoint, the ends of said platform then deflecting downwardly by gravity to produce a level top surface, said downward deflection of the ends serving to tension at least some of said reinforcing rods or cables. 